I have a very non-standard storage setup at home. The setup is made up of a 3x500G raidz array on ZFS hosted by OSX. For the longest time I could not get files to copy over samba on ZFS. The files would stream just fine but not copy over, they would abort at the 99% transfer point. Well, I have finally found the fix for it; turn off extended attributes!

smb.conf

#vfs objects = notify_kqueue,darwinacl,darwin_streams
vfs objects = notify_kqueue,darwinacl

; The darwin_streams module gives us named streams support.
stream support = no
ea support = no

; Enable locking coherency with AFP.
darwin_streams:brlm = no

As Charles Heston would say, You can have my ZFS when you pry it from my cold dead hands.

viva ZFS on OSX!